Risk management of chemicals and contaminated land – from planning to verification - Environmental Deterioration and Contamination: Problems and their Management - page 269

Figure 9.8 Integrated risk model for contaminated sites.
QSARs modeling environmental fate properties and effects of chemical substances are
mainly used for the purposes of generic RA (see Volume 2).
4.3 ERA of contaminated land
Methodologies and theory for contaminated site risk assessment have been developed
in connection with national remediation programs introduced for the massive assess-
ment and clean-up of contaminated land all over the world, in particular in the US and
Europe. In the course of these programs the management steps were elaborated and
practical tests were conducted: inventory making, defining priorities, assessing the pri-
ority sites in detail, evaluating the management and RR options and implementation,
monitoring and verifying the applied technology.
After performing the ERA of a contaminated site, the next risk management step
is to determine the “no risk'' level with respect to future land uses. Quality criteria
relevant to future land use should be established ( PNEC future for the ecosystem and
the relevant reference value —DNEL future or RfD future —for humans), and an inverse
risk-assessment procedure should be used to calculate the targeted environmental con-
centration in the source, on the pathways or in the vicinity of the receptors to ensure
an acceptable or no-risk situation.
Following this concept, the dominant risk should be identified and used as a rele-
vant basis of the calculation. In order to create the integrated conceptual model of the
site (Figure 9.8) the pollutants must be identified, a relevant transport model estab-
lished, and a good concentration estimate for the environmental compartments (air,
soil, groundwater, surface water, sediment) provided. When the site-specific land uses
are known, the exposure model can be compiled.